The invention pertains to an electric motor, in particular for raising and lowering panes in a motor vehicle according to the type of the independent claims. Numerous electric motors for this purpose are already known, for example from EP 0 474 904 B1. The electric motor shown in this patent document shows a transmission and integrated control electronics with a printed circuit board on which the commutator of the electric motor are located. Since the distance between the pole housing and the transmission housing in which the commutator of the electric motor is arranged is very short, the printed circuit board has an extension which guides the brushes of the electric motor to the commutator located on the armature shaft. This form is both cumbersome and expensive both from a manufacturing and an assembly perspective, in particular when Hall sensors need to be located in the area of the armature shaft for monitoring a transmission position.
The electric motor according to the invention having the distinguishing features of the main claim has the advantage that it is small and flat and in addition is compatible with a simple, essentially rectangular printed circuit board.
The features described in the dependent claims make possible advantageous further embodiments and improvements of the features according to the main claim.
If the electric motor has in addition a commutator extending over the pole housing, the brush holder can be directly connected mechanically and electrically with the connector plug, through the printed circuit board.
A groove in the brush holder for receiving the essentially rectangular printed circuit board represents an additional advantage, since this allows the printed circuit board to be precisely positioned. Due to this lack of tolerance channel connections for the plug and for the brushes can be brought directly to the printed circuit board.
A further advantage is if suppressors, which typically need to be located on the brushes, can be mounted directly on the printed circuit board.
If the printed circuit board having an ASIC (an Application-Specific Integrated Circuit) is equipped with an integrated Hall sensor, this has the advantage of replacing a number of the components and this also reducing cost.
It is particularly advantageous if the printed circuit board extends at least over the length of the commutator, especially if it extends beyond it by a factor of two or more. This leaves sufficient room for locating the electronic components of the control circuitry, especially depending on the required power.
If the brush holder carries a segment extending along an armature shaft, with this segment at its end at least is formed as a part of a bearing support, the armature shaft is rigidly held in place in the area of the commutator and in particular the distance between a transducer magnet located on the armature shaft and a Hall sensor located on the printed circuit board is kept constant.
By using holding elements for suppressors, the latter can be located in the area of the brushes with low vibrations, which has the advantage of increasing the life expectance of the suppressors.
Particularly advantageous are arch or bridge shaped connecting bridges between the printed circuit board and the plug. In this way the connecting bridges are insensitive to the pulling and pressing forces that occur as a consequence of the mass inertia when the vehicle experiences vibrations. This ensures good contacting of the plug.
An additional advantage is provided when there are no conductor paths on the printed circuit board in the area of the brush sparking between the brushes and the commutator. These conductor paths would be easily damaged or corroded by spark discharges spraying in this area and the like.
If the printed circuit board is attached at at least one additional point besides the groove, the result is a stable connection between the printed circuit board and the brush holder.
If the suppressors are attached in holders on the brush holder, it is particularly advantageous to attach the printed circuit board using the attached suppressors. This enables easy and rapid installation of the printed circuit board.
It is particularly advantageous if the printed circuit board is held at segments also having a bearing receptacle for the armature shaft. This holds the distance between transducer magnets attached to the armature shaft and a Hall sensor mounted on the printed circuit board constant even during strong vibration.
A significant advantage can also be realized by the fact that the printed circuit board, especially when it is formed as a plug-in module, can be inserted into the transmission housing. This makes it easy to replace the control electronics. The term xe2x80x9ccontrol electronicsxe2x80x9d, as commonly known, designates generally all components that serve for electrically controlling the electric motor. Such control electronics have a printed circuit board, which includes a concrete switching arrangement on a substrate.
If the connector plug is mechanically and electrically connected to the printed circuit board, a plug-in module having an integrated connector plug can be used, which significantly simplifies the contacting of the connector plug. This applies especially if clamping electrodes are used for contacting the brushes.
It is also advantageous to attach the plug or the plug-in module to the transmission housing using a flange connection. This ensures that the plug-in module is held securely, and makes it possible to use corresponding seals to easily make the assembly watertight.